Dynamic Cyclodipeptide Clamps as Enantioselective Receptors toward Vitamin K1.

Abstract

We report the design of folded cyclodipeptides that show dynamic and adaptive conformational transitions responding to solvents and enantioselective recognition of a biomolecule, vitamin K1 (VK1). Postmodification of phenylalanine-based cyclodipeptides with polycyclic aromatic hydrocarbons (pyrene, anthracene, and phenanthrene) produced chiral folded structures. Compared with other solvents, these cyclodipeptides exhibit ultrahigh sensitivity to dimethyl sulfoxide (DMSO), which induces a conformational transition from parallel to perpendicular dimerization. It leads to a reversed screw sense of the chromophores, facilitating tunable chiroptical properties. In a mixed DMSO/water system, the folded cyclodipeptides perform as efficient molecular clamps that recognize VK1 through charge-transfer complexation. Additionally, d,d- and l,l-configured cyclodipeptides displayed enantioselective recognition of VK1, as evidenced by differences in binding affinity, circularly polarized luminescence and self-assembled nanoarchitectures. This study provides approaches for artificial receptors and chiral sensing based on cyclopeptides.